Neil Young, who released his memoir Waging Heavy Peace this week, stopped by the Late Show with David Letterman last night to talk about the book – but not before Jimmy Fallon came out for a special homage to the singer he called "my favorite guy." Armed with an acoustic guitar and harmonica, Fallon offered Letterman his take on what the theme from The Fresh Prince of Bel-Air would have sounded like had Young recorded it.